1. Field of the Invention
The present invention relates to a container packaging apparatus, and in particular to a container packaging apparatus for packaging a container, for example, a wafer case containing a plurality of semiconductor wafers therein, so as to be packed in a packaging bag, such as a plastic bag.
2. Description of the Related Art
In order to prevent any damage or contamination during being transported, semiconductor wafers, such as silicon wafers, which have been manufactured in a wafer manufacturing plant are typically loaded into a wafer cassette, an intermediate holder, made of synthetic resin, which is in turn packed in a wafer case whose cover can be closed tightly via a gasket (a packing member). The wafer case is further packed firstly in an inner bag made of nylon (the trade name of polyamide fiber) and then in an outer bag made of aluminum, in which the wafer case may be enclosed in respective bags via heat sealing. This provides a packaging structure that can prevent any external fine dust or the like from entering into the wafer case to form a deposit on the wafer surface during the transporting operation.
To carry out manually the packaging procedure as described above, firstly the container is inserted into the packaging bag, and then the packaging bag in its sealing area is set in a heat sealing machine or a pressure sealing machine which may carry out the sealing operation with or without deaeration. Subsequently, an opening region and a rear end portion located opposite to the opening region of the packaging bag are folded manually, and both of the end portions of the packaging bag are fixed securely with tape attached thereon, respectively.
If all of the above steps are carried out manually, it takes a considerably long time to accomplish the packaging procedure and adversely it tends to develop crimps in the sealed area. In addition, when carrying out the packaging process incorporated with the deaeration effective in the bag, the condition after the deaeration varies widely, inhibiting the stable packaging procedure to be accomplished. Further disadvantageously, the process of folding and fixing the end portions of the packaging bag by attaching the tape has also imposed a lot of troubles.
There is one known apparatus to address the above problem, including a container packaging apparatus as disclosed in the cited reference, Patent Document No. 1, for example. The container packaging apparatus disclosed by the cited Patent document No. 1 allows for the packaging procedure to be carried out by the divided steps, where the container packaging apparatus comprises: a packaging bag supply means for supplying a transverse-mounted packaging bag into a predetermined position; a container loader means for supplying a container to be packed into a predetermined position; a container insertion means operable to hold by vacuum chuck an opening region of a packaging bag with the aid of a pair of vertically arranged suction arms so as to open the packaging bag in the site of the opening region by moving each of the pair of suction arms vertically away from each other and subsequently to insert the container into the packaging bag through thus opened opening of the bag; a shaping means operable to deaerate the packaging bag containing the container packed therein by a suction nozzle and subsequently to make a heat-seal for closing the opening by a pair of upper and lower sealing bars; and a packaging bag end portion processing means operable to fold an end portion of the sealed packaging bag and fix the folded end portion of the packaging bag.
According to the cited Patent Document No. 1, in the packaging process for carrying out the steps including, inserting the container into the packaging bag; deaeration and packing of the container; heat sealing in the opening of the packaging bag; folding the end portion of the packaging bag; and attaching the tape (label), the packaging apparatus can make the packages uniform in their quality, even if containers different in size, shape or the like are mixedly transferred through respective steps, so as to facilitate mechanization and automation of respective processes and thereby improve a throughput in the packaging procedure.
[Patent Document No. 1]
Japanese Patent Laid-open Publication No. 2002-154505
However, in the cited Patent Document No. 1, when the packaging bag with a container housed therein is deaerated via suction nozzle, the deaeration operation is typically carried out without any solution to position and hold the both side ends of the opening of the packaging bag in place. The apparatus of the cited Patent Document No. 1 has the following drawbacks in association with this manner of the deaeration.
Specifically, crimps are more apt to appear in the opening region of the packaging bag during the deaeration operation, and the heat sealing operation in the opening region, if subsequently applied as in this condition, would cause a problem in the sealing property of the packaging bag. In addition, owing to the crimps developed in the sealed area, the left and the right triangular ear portions in the front end portion of the packaging bag tend to emerge unevenly in its size and shape Consequently, when each of the triangular ear portions in the front end portion and the rear end portion of the packaging bag is folded and fixed with the tape in both sides with respect to the container, the triangular ear portions formed in the front end side of the packaging bag could not be long enough to be fixed well, inhibiting respective sets of triangular ear portions, each set including one in the front end portion and the other in the rear end portions of the packaging bag, from being fixed together by using a predetermined length of tape, and thus the packaging of the container with a resultant high level of quality and the stability during the procedure could not be obtained.
In the light of the above circumstances, the inventors of the present invention have made an enthusiastic research and realized from their research that if the both side ends of the opening region of the packaging bag are positioned and held in place by a side edge chuck means during the deaeration operation, there would be substantially no crimps developed in the opening region of the packaging bag during its being deaerated. This can help provide the packaging bag with a high level of sealing property and a solution to eliminate the unevenness in size and shape between the left and the right triangular ear portions in the front end portion of the packaging bag resultant from the crimps. The inventors of the present invention have accomplished the invention based on their further finding that respective sets of triangular ear portions, each set including one in the bag front end portion and the other in the bag rear end portion, can be fixed together well securely with the tape on either side surface of the packaging bag, thereby providing the packaging of the container with the resultant high level of quality in the stable manner.